The invention relates to a sanitary mixing valve having two valve disks arranged in a cartridge casing, one of which is held in a rotationally fixed manner while the other can be moved by a driving element provided on a spindle, said driving element consisting of a part, which is connected fixedly to the spindle and has a gearing in at least a portion of its outer circumference, and a coupling, which has on its inner circumferential surface a gearing which, in the installed state, engages with the gearing on the fixedly connected to the spindle part of the driving element, the coupling having at least one stop projection which[, in cooperation with at least one stop,] limits the rotational movement of the driving element in cooperation with at least one stop.
With such known mixing valves, such as disclosed in European Patent Application 745,798, U.S. Pat. Nos. 5,467,799, 5,826,615 and 5,832,952, the position of the movable valve disk is altered in relation to the rotationally fixed valve disk by the turning of the spindle by means of the driving element so that cold water, mixed water or hot water can flow through the valve, depending on the position of the two valve disks relative to one another. In most cases, the movable valve disk can also be brought into a position opposite the fixed valve disk by means of the driving element, causing the valve to be shut off. To maintain the rotational movement of the movable valve disk in the range required for operation of the mixing valve, the driving element has at least one stop projection which, in cooperation with at least one stop on the cartridge casing, limits the rotational movement of the driving element and thus of the movable valve disk. This stop may be equivalent to a temperature limit if it causes mixed water to flow even in the hottest setting, i.e., the cold water opening in the fixed valve disk is not entirely closed. In the case of a fixed disk, however, the temperature of the mixed water coming out of the faucet in the position described last is obtained from the starting temperatures of the hot and cold water and [from] the pressure of the incoming hot and cold water. Due to the fact that the driving element consists of a part, which is fixedly connected to the spindle and having a gearing in at least one area of its outer circumference, and a coupling, which has on its inner circumferential surface a gearing which in the installed state engages the gearing of the fixed part of the driving element, the stop projection on the driving element can be offset by offsetting the coupling with respect to the fixedly connected part of the driving element according to the gearings, and thus the range of rotation of the driving element and the movable valve disk, however, the maximum temperature of the water coming out of the faucet is also changed. According to the pitch of the gearing, this yields a minimal angle of the offset for the stop and the adjustability of the maximum temperature in certain stages. For reasons involving the manufacturing costs and the required robustness of the driving element parts, there is a limit to how thin the teeth may be and thus also to how small the parts may be, and the adjustable gradations in the maximum temperature are not satisfactory.
The object of the present invention is to design a sanitary mixing valve of the type defined in the preamble so that a finer precision in adjustability of the maximum temperature is made possible without greatly increasing manufacturing costs or having a negative effect on the robustness of the driving element parts.
This object is achieved according to this invention by the fact that at least one first stop projection extends beyond a portion of the height of the coupling, and at least one second stop projection whose stop surface is offset relative to the stop surface of the first stop projecting, extends over-another portion of the height, and the coupling can be placed on the fixedly connected part of the driving element in two different directions, and the first and second stop projections cooperate alternatively with the stop provided in the cartridge casing.
The offset of the stop surfaces permits intermediate steps between the gradations resulting from the pitch when the coupling is placed on the fixedly connected part of the driving element in the opposite direction.
In the installed state, the fixedly connected part of the driving element together with its area having the gearing preferably projects out of the cartridge casing through a central opening in the cartridge cover, and the coupling is placed on the fixed part from the outside, engaging with the minimum of one stop projection in the orifice in which the sixth stop with the cartridge casing extends radially. The coupling can thus be removed from the fixed part of the driving element, rotated and reattached without having to open the cartridge.
The pitch of the gearing on the outer circumference of the fixedly connected part of the driving element and on the inner circumferential surface of the coupling is preferably 10xc2x0. With the usual dimensions and materials used for cartridges of mixing valves, this 10xc2x0 pitch of the gearing yields an acceptable gradation for adjusting the maximum temperature without any risk of the material of the driving element breaking off in the area of the gearing.
The offset preferably amounts to half the pitch of the gearing on the outer circumference of the fixed part of the driving element and on the inner circumferential surface of the coupling, so that due to this offset, intermediate steps are possible between the steps that are possible due to the gearing, these intermediate steps being located exactly in the middle between two steps according to the gearing.